Antiaircraft fire control predictor



e 1945- E. w. CHAFEE ETAL 33 9 v ANTIAIRCRAFT FIRE CONTROL PREDICTOR Filed Oct. 5, 1957 A Sheets-Sheet 2 June 1945- E. w. CHAFEE ET AL 2,378,910

. ANTIAIRCRAFT FIRE CONTROL PREDICTQR Filed Oct. 5, 1937 4 Sheets-sheet 3 1N VE N TORS EHRL CHAFEE fifiwvo WITTKUHNS June 26, 1945'. w, HAF ET'AL 2,378,910

' ANTIAIRCRAFT FIRE CONTROL PREDICTOR Filed Oct. 5,1957 4 heet 4 Cavsm/vr S urn floral? INVENTORS EARL h! 014F155 QM/V04. Mrr/ru/vms;

?atented June 26, 1945 7 ounce smrss PATENT ores-es 2,378,910 surmmcnarr mu conrnor. rnsnro'ron Earl W. Ghafee, New York, N. Y., and Bruno A. Wittkulms, Summit-N. 3., assignors to Sperry Gyroscope Company, 1110., Brooklyn, N. Y., a corporation of New York Application @ctoher 5, 1937, Serial No. 167,358

14 Claims. (Cl. 235-615) This invention relates to fire control directors. particularly of the anti-aircraft type, wherein the relative speed of the target is great. This application discloses in greater detail how the rate determining and introducin means disclosed in our "prior application Serial No. 75,526, filed April 21, i936, now Patent No. 2,206,875, dated July 9, 1940, for Fire control devices, is applied in a complete modern director of the type disclosed in the prior patent to Earl W. Chaise, Hugh Murtagh and Shierfield G. Myers, No. 2,065,303, dated Decemher 22, 1936, for Apparatus for control of sun fire. one present application is therefore a continualion. in part and further amplification of our aforesaid prior application.

A further object of the invention is to improve this system of fire control by adapting it for sliding targets by introducing a means for determining rate of change of altitude as well as the resolved :1: and 1! rates in a horizontal plane;

llieierring to the drawings, illustrating the invention in diagrammatic form,

Figs. 1A and 1B are the two halves of a diagram showing the principal component parts of our nvention, Fig. 151 being a substantial reproduction of Fig. 1A of Patent 2,065,393and Fig. 1B showing the new rate means in place of the tachometers oi the patent, plus the elevation rate device.

Fig. 2 is a diagrammatic view showing on a larger scale the mechanism for determining the target displacement during the time of flight or the shell, this figure being substantially the same as l lg. of our aforesaid prior application. 4

Fig. 3 is a plan view of one of the resolving mechanisms, being taken from the aforesaid prior patent.

the. e is a modification of the arrangement of 2 and is suhstantially'the same as Fig. 3 of our prior application above referred to.

as explained in said prior patent, the sights ET and AT are maintained on the target by the elevation handwheel EH and the azimuth handwheel All, the latter rotatin the entire director and sights around fixed gear l. Altitude is also continuously fed into the machine from a height tinder (not shown), through repeater motor The elevation angle E0 appears at Eu and lilo on 4 the coarse and line indicators 23 and 23 and the Said cam is positioned laterally by means of shaft l? on which its support ll is threaded,said shaft being turned from present range setting handle 83. The com is also rotated in accordance with the altitude Ho from handwheel H which is turned until index it matches'pointer are. The

" lift of cam pin it rotates, through lack and pinion so and shafts 2i and 22, the pointers tit and 223 on the elevation angle indicators E0 and E0. The cam is so laid out that with the correct height Ho and elevation angle E0 set into the machine, the rotation of the present range handle it tomatch the pointers and indices of indicators pointer and index 228' and 23' read on the. dial 225'. As the elevation angle changes, the operator of handle it preferably shifts to the range rate handle 26. This handwheel turns a dial 25 and,

nositlons the shiftalole member oi a change speed device. As shown it positions hall or balls 26 operating between a disc ill turned iroma constant speed motor 29 and a cylinder 29. Said cylinder operates the same shalt a the handwheel 93 through a differential time when handle is set so that follow the -nointer indicators E0 and E0 stay matched, the correct rate of change or range has been set up. Similarly,

as the altitude changes, the operator shifts to handle H which positions the shiftable member 9% of similar variable speed device 29 which turns the same shalt it through differential it to position cam it rotationally by turning shalt it. Shaft 3t not only positions cam it anially, as explained, out also operates the cross shaft 38' and the shafts 32 and driving present range into the present position resolving mechanism 33 i, and also leading to the future mechanism 355.

Similarly the azimuth angles A0 are set in trom the handwheel All through shafts 8t, 37] and. lit, the latter being connected to the present mechanism through shaft is and to the future mechanism through shaft it. Said mechanism are preferably superimposed and may; he of identical construction (see also Fig. 3). Each mechanism may comprise a large gear 35 having a spiral groove $2 in the upper face thereof. Said,

gear, in the case of the present mechanism, is turned from the range shafts lit, as through a pinion 55. Superimposed thereon is a second concentrically mounted gear or plate it having a radial slot therein which is rotated by a pinion 56 on the azimuth shaft 3t. In said slot is slidably mounted a block a? having pins and rollers thereon, the lower roller engaging the spiral range gear or disc II is set in accordance with the present horizontal range and .the azimuth gear or disc 43 is set in accordance with A0. The differential 50' is for the purpose-of preventing the range from being changed when only A is being changed by causing the two gears to move together under such conditions.

As above stated, the future resolving mechanism may be quite similar in construction but in this case the range gear ll'- is rotated by a shaft 33 which is driven not only from the present range shaft 3! but also from a range difference motor, 98 or change of range motor through a differential 81. Similarly the azimuth gear 43' is driven from shaft 40 which is rotated not only by the shaft 38 but also from the "azimuth difference motor 98 through shafts 80 and I00 and differential IN. The vertically movable slide 52 in this instance is shown as turning a shaft H0 through rack and pinion HI. On said shaft is mounted one portion 88' of follow-up contacts 8645'. Plate or slide 5!, on the other hand, is

shown as turning through similar rack and pinion I ll one portion 83' of follow-up contacts 83-83, the complementary contacts in each case being driven by one or the other of the range-or azimuth difference motors as was more fully explained in the aforesaid patent.

Returning to the present resolving mechanism, the rates of movement of the two slides BI and I2 are, of course, proportional to the rate of displacement of the target in the two component directions. To determine such rates, we actuate from the up and down movements of slide 52, a shaft 56 through a rack and pinion connection 51; and through a similar connection 51' we operate the shaft 58 from the right and left movement of slide".

Shafts SI and 58 both are connected (the latter byway of shaft 53) to rate and displacement determining devices which constitute a marked improvement over the rate and displacement devices of said prior Patent 2,065,303, and which are substantially'the same'as shown in Fig. 5 of our aforesaid application, now Patent No. 2,206,875,

reproduced herein as Fi 2; The essential element of the device is a variable speed gear comprising a power driven disc,. a radially adjustable ball carriage thereon, a cylinderdriven thereby and a three arm diil'erential, one arm of which is driven by displacement of the target along one axis, another arm of which is driven by the cylinder of the variable speed drive and the third arm of which is operatively connected to adjust the radial position of the ball carriage thereof. With such an arrangement, if the disc of the variable speed gear were to be driven at a constant speed (as is disc 215 of Fig. 4 referred to hereinafter), the position of the ball carriage would be automatically-adjusted, radially, on the disc so that tance of the ball carriage from the center of rotation of the disc would be a measure of the target's rate of displacement R along the chosen axis. In the arrangement of Fig. 2 an additional factor is introduced by varying the speed of rotation of disc 15 in accordance with the reciprocal of time of flight of the shell the two factors, It and being thus divided, as will be explained more in detail hereinafter, to give RT, the predicted disdrives, without the self-adjusting feature derived from the connection to the differential, are also employed where it is desired merely to convert a displacement into a rate of rotation, as will be described in connection with the introduction of and the wind correction. 7

As shown in Fig. 2, the a: component of target displacement is supplied to the z prediction computing device by way of shaft 63 which drives one arm of wind correction differential 59, the'middle or second arm of which is driven from roller 10 of wind correction variable speed gear II and 'the third arm of which drives one arm of a sec- 0nd diflerential I! by way of shaft I09. The op posite or second arm of said differential I2 is driven by roller 13 of the prediction variable speed gear I4, while the third arm radiall positions the ball or balls 15 of gear 14 on rotated disc Said disc, as has been noted, is rotated at a variable speed from the roller 11 of a third variable speed gear I8, the radially adjustable balls of which, driven'from disc 80, are positioned by a cam pin I9, riding on cam T, whose-lift is inversely proportional to the time of flight of the when a state'of equilibrium was reached, the dis- 7 shell,-i. e., proportional to constant speedmotor III, which may also serve, as the source of power for the constant speed discs of the a: wind correction mechanism 'Il (disc I02) and the 1 wind correction mechanism I83 (disc I84, Fig. 113). Disc 15 is therefore driven from cylinder I! at a rate proportional to and since, when the self-adjusting variable speed gear comprising gear 14 and differential 12 reaches a state of equilibrium, the rate of rotation of cylinder 13 must be equal to or proportional to the rate of rotation of shaft L09, ball carriage I5 will be automatically positioned to impart such speed to cylinderlt. In this self=adjusting arrangement diiferential 12 serves as an equalizer of the speeds of-shaf-t we and cylinder 73, since if these speeds, as fed into two arms of the differentiaL are unequal, the third arm of the differential'is caused to rotate shaft I85 and thereby through pinion. Em and rack I86 change the radial position of ball carriage until equilibflum is established. The radial displacement oi oi ball carriage iii when this equalizing action is completed, will, upon analysis, be found to be greater the less the speed of disc the greater the speed of shaft lfiiHR). In mathematical f product, which is measured by the displacementci carriage Ell, is transmitted as the angular displacement of shaft use, geared to racl: bar HES, connected to ball carriage it through pinion er, and is added to the displacement of slide it rep= resenting" present position of the target, by way of shaft Eli and diiferential use, to position the future a slide i in accordance with the future or predicted position of the target through a power multiplying device hereinafter described.

The wind correction obtained from device ll the rate oi rotation of cylinder ii! is added to the rate of target displacement as an accelerating or retarding factor by the differential 5% so that it is this corrected rate that is fed into differential l2 shaft The ball carriage MB of the wind device it is radially displaceable by handwheel 2% in accordance with the :6 component of wind velocity effective in deflecting the shell. Such displacement causes cylinder it! to be driven at a velocity proportional to the correction to target velocity necessary to compensate for the wind-induced deflection or retardation of the shell. In this manner the ram of change of target position, as represented by'the rate of rotation of shaft 33, is corrected for the effect of wind velocity before being multiplied by T in the operation of computing predicted target displacement during the flight oi the shell.

The prediction mechanism for the y axis may be identical with that above described. Shafts 56 and 6 l are connected to the y wind correction device 583 (Fig. 1E), by way of which a wind correction is set by knob and also to device 538 for obtaining theprediction correction along the y axis. The disc of device 838 may be rotated from the same device 10 that rotates disc E6 of device is. The

-, height or altitude predicting means, so that the director is'equally well adapted to predict the position of gliding targets.' We again employ the output of device 78. having a rate of rotation proportional to l H to rotate disc I38 of variable speed device E and we feed into equalizing differential E35 of the al= titude prediction self adjusting variable speed gear (1) the height of the target as determined by the settings .of handwheels H, H, which set in a displacement and a rate of change of displace= merit, respectively, and as measured by the angular positions of shafts to, st, 38, it and 39', and

(2') the rotation of cylinder E35, so that in the radial position which ball carriage it? takes up, its distance from the center of the driving disc is proportionalto the quotient of rate of altitude change and functioning in a manner similar to contacts tit,

and 86, ct) and differential Edi to give shaft l lil an angular position representing future alt-i tuole.

We employ this future altitude to position in one dimension, say axially, the time of flight cam T and preferably also the uadrant elevation cam QE and the fuse setter earn F. Said cams are rotationally positioned in accordance with future horizontal range R from shafts Q3 and Q2.

The apparatus sliown diagrammatically in Fig. 4 is a modification of the arrangement of Fig. 2 for predict hange of target position during the and may be employed forprel or all of the three axes, certain elements being included to adapt the apparatus to prediction in the horizontal plane which may be dispensed with for altitude or height predic tlon, as will be pointed out. The displacement of slide 256 (corresponding to slide it of Fig. 2) represents target displacement along a chosen axis and is transmitted by gearing to shaft 2&3 driving one arm of (inferential H2, a second arm of which is driven by roller 2.15s oi variable speed device Zl'i. In this device, the disc 2% is driven at a constant speed from motor 2st and, in accordance with the previously described operation of such self-ad lusting variable speed devices, when equilibrium is reached, ball carriage its is displaced from the center of disc 2% an amount which causes roller 2113 to be driven at the same speed as shaft 2%. Smce, with disc 276 driven at a constant speed, the roller speed varies directly and solely with. the displacement of the all carri e, i displacement represents rate of change of target position along the chosen axis.

- The references to slides 25B and 25V in the above description of the prediction mechanism of components of present and future target position Fig. 4 relate more particularly to the' mechanism for calculating prediction in the horizontal plane wherethe displacements of these slides represent changes. It will readily be appreciated that, for altitude prediction, where according to Fig. 1B

present and future target altitude are represented by angular positions only, shafts 263 and Ill will not be geared to the aforementioned slides but that present altitude, as represented by the of Fig. 2, time of flight is introduced into the prediction self-adjusting variable speed device by way of disc 16, so that the displacement of the ball carriage of said device represents the product of the two factors, rate of change of target displacement and time, while in the arrangement of Fig. 4 the disc of the variable speed device is .driven at a constant speed and the displacement of the ball carriage represents target rate only, which is multiplied by time by independent cam means. As noted, either of the two arrangements may be used in obtaining change of target position along any of the three axes.

Returning to the future resolving mechanism, each of the two slides 52' and 5| of the future mechanism positions a contact, 86' or 83', cooperating with one or the other of contacts 88 and 83, as hereinbefore explained. Said contacts operate the range difference and azimuth difl'erence mo-- tors 56 and 98 preferably through the connections more fully explained in Patent No. 2,065,303. Thereby the future resolving mechanism receives the predicted coordinates of the target's position from which the future range Rp and future azimuth angle Ap may be determined by the angular position of the two gears II and II. The former is represented by the rotation of the shaft 83 and the latter by the rotation of the shafts 40,10, which is indicated as future azimuth by the coarse and fine dials Ap and A Into said dials corrections may he introduced from the handwheel I which rotates the fleld of the A transmitter Hi5 transmitting the future azimuth angle to the gun through the cable I08- A consideration of the problem being solved by the future resolving mechanism will show that knowns, the machine operating by what may be termed the flow method by which the correct future positioin is obtained very quickly although every change in each variable'alters the setting for the other variables. Therefore, .both motors in a limiting sense.

98 and 88 operate simultaneously and each in-' fluences the position of the other.

Since the gunners must know the quadrant elevation at which the guns must be pointed, which is the sum of the future elevation angle and the super elevation, and since both future elevation and superelevation are functions of future horizontal range R9 and altitude Hp, we prefer to compute the sum of the two on the samecam QE to give quadrant elevation. Future range Rp'represented by the rotation of the shaft 83' may, therefore, be used torotationally position the cam shaft '2 of thecams QE, F and T.

With the quadrantelevatio'n cam properly laid out, therefore, the lift of the pin H2 thereon will represent the quadrant elevation, i. e., future elevation plus superelevation, this lift being transmitted through rack and pinion H3 to rothe transmitter H! to the gun. Similarly, fuse corrections may be introduced through the handle I20.

As many'changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from .the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not Having described our invention, what we claim and desire to secure by Letters Patent is:

1. In a fire control predictor, means actuated in accordance with the present position of the target, a future position means, and means for advancing said second means ahead of said first means in accordance with the advance in position of the target during the time of flight of the shell; including power actuated mechanical means for converting the movement of said'flrst. means into a positional displacement proportional to rate, means actuated directly from said displacement for multiplying said displacement by function of time, and means actuateddirectly thereby for positioning said second means. 7

2. In a fire control predictor, means actuated in accordace with the present position of the target, a future position means, and means for advanc ing said second means ahead of said flrst means in accordance with the advance in position of the target during the time of flight of the shell, including a driving member, a frictional driven intermediate member, the'speed ofwhich relative -to that of the driving member varies with its position thereon, athird member driven by said intermediate member, said intermediate member being differentially positioned by said present' position means and said third member, means positioned by the position of said intermediate ber positionable to effect change of output speed thereof, said change speed member being positioned in accordance with the wind velocity effect and the resultant output motion of said device added to the motion of the present position means in differentially positioning said intermediate member.

4. In a fire control director of the rectilinear plan coordinate type having means for determining the time of flight of the shell and quadrant elevation determining means, means for feeding in constantly changing altitude as I determined by a height finder, a constant speed motor, a variable speed .device and differential gear interconnected for automatically determining from said altitude data rate of change of I altitude, said variable speed device being driven by said constant speed motor, means for com= billing rate of change of altitude with time of flight to obtain altitude change during flight of the shell, and means for feeding the sum of altitude and change of altitude to said quadrant elevation determining means for positioning the same according to future altitude.

5. In a fire control director, means for continuously resolving the targets position into rectilinear components, self-adjusting variable speed devices equal in number to said components, each including diflerential means interconnecting movable members thereof, means for actuating each of said devices iointly in proportion to change of one of said components and time of flight of the shell for positioning a mem bet" in accordance with the product of the rate of chan e of actuating component and time oi flight, said product representing change of said.

target position cemponent during flight of the shell.

6. In fire control director having individual means til idle represent component changes 0 It position along each of three coordinate es dining flight of the shel ns 7. In a me central director, means fer com a puting quadrant elevation including a three di mensional cam and a card follower, said cam and follower being mounted for relative rotation and axial movement to raise or lower the follower,

future range means for imparting one of said movementsand future altitude means for llll'" parting said other movement including present altitude means, time of flight means, an inter connected variable speed device and difierential gear adapted to receive present altitude and timeof flight and automatically compute there= from change of altitude during the flight of the shell, and means for combining present altitude and change of altitude to obtain future altitude, said cam being laid out so that the at each point represents quadrant elevation for the corresponding future range and altitude.

8. In a fire control director, means for com tinuously resolving the target's position into rec tilinear components fixed in azimuth; individual self adjusting variable speed gears actuated irons. each component movement, the adjustable ele- ,ments of which position themselves from a reference point proportionally to a function of the rate of movement along each component, and means for further causing the positions of said elements to be; proportional to a function of time of flight of the shell, means for combining the displacements of said adjustable elements as representing component changes of target position during flight of the shell with said components of the target's position to give future coordinate positions, and means for reconverting said last named positions into future target elevation and bearing.

9. In a fire control predictor, means actuated in accordance with the present position of the target, a future position means, and means for advancing said second means ahead of said first means in accordance with the advance in position of the target during the time of flight of the shell, including a differential gear and a selfadjusting variable speed gear into which said first naxned means feeds, said variable speed gear having a driving element and a. self-adjusting driven element, said self-adjusting feature being obtained by interconnection to said difierential for setting a wind correction into the same, and

means for algebraically adding the output there-- of into said present position means, whereby the future position is also corrected for wind deflec ticn.

ii. A fire control director as claimed in claim 5 in which said variable speed devices each in= elude a member rotated in accordance with time of night and said positioned member is a ball adivstably positionable away from the axis of ro-= tation of said rotated member to be driven at a variable speed thereby.

12. In a fire control director of the rectilinear plan ccordinate type having means for determin ing the time of flight of the shell and quadrant elevation determining-means, means for feeding in constantly changing target altitude as determined by a height finder, a self-adjusting varia ble speed device including differential means in terconuecting movable members thereof, said device havins a member automatically positioned in accordance with a function of two variable quantities actuating said device, meansfor supplying a function of time of flight to said device as one of said quantities, means for supplying rate oi change of altitude as the other of said quantities, change oi position of said member then being a measure of change of altitude during the flight of the shell, and means for positioning said quadrant elevation means in accordance with the sum oi present altitude and said change of altitude, said sum representing future altitude.

13. In a fire control director future altitude means, comprising means for, continuously setting present target altitude as determined by a height finder, time of flight means, a, variable speed device including a driving member actuated by said time of flight means in accordance with a function of time of flight, a positionable intermediate member driven thereby and a third member driven by said intermediate member at a rate governed by the position of said intermediate member, means actuated jointly by said present altitude means and said third member for positioning said intermediate member to cause said third member to be driven at a rate proportional to rate of change of present target altitude, said intermediate member being thereby displaced from a reference position in proportion to the product of said rate and time of flight, and means for combining the displacement of said intermediate member, as representative of change of target altitude during flight of the shell, with present target altitude to obtain future target altitude.

member in proportion to the quotient of rate of change of altitude and the reciprocal of time of flight, displacement of said last member thereby representing predicted change 01' altitude dur- 5 ing flight of the shell.

EARL w. enamel BRUNO A. wn'rxurms. 

